Ray, Blonde

Raja brachyura

Method of production — Caught at sea
Capture method — Demersal otter trawl
Capture area — North East Atlantic (FAO 27)
Stock area — Irish and Celtic Seas
Stock detail

7a, f and g


Picture of Ray, Blonde

Sustainability rating five info

Sustainability overview

The stock status is unknown and there is conflicting information about the population trends. Blonde ray is relatively vulnerable to fishing because it matures at a large size and produces relatively few young. As a result, young blonde rays can be overfished before they have had a chance to reproduce.

There is no specific management plan for skates and rays in these waters. They are managed under a total allowable catch (TAC) for many skates and rays but greater protection is needed. Greater monitoring is required.

Demersal otter trawling is associated with discarding of unwanted fish and potential ETP species; capture rates can be reduced with appropriate gear modifications.

Biology

Blonde ray are an inshore species belonging to the Rajidae family of skates and rays. Maximum length is 110 cm. Length at maturity is 81-83 cm at ages 4-5 years. Found predominantly on sand and steep sandbanks and commonly occurs at depths from 14-146 m. Relatively few eggs are produced, meaning that few juveniles will be produced each year. In the English Channel, females with well-developed eggs occur from February to August. Eggs are laid in cases known as “mermaids purses”. Blonde ray breed in the Bristol Channel in April and May. Although it has a relatively broad geographical range, this species is most abundant from the British Isles to Portugal. Blonde ray is relatively common in inshore and shelf waters (down to about 150 m) in the English Channel and Irish Sea, Bristol Channel and St George’s Channel. Blonde rays are particularly vulnerable to depletion due to their late age at maturity, slow growth and they produce few young. Little is known about connectivity of blonde ray stocks, yet, connectivity is crucial for managing skates and rays and provides a long-term perspective of their population trends.

Stock information

Criterion score: 0.75 info

Stock Area

Irish and Celtic Seas

Stock information

The state of the stock in the Irish and Celtic Seas is unknown.

There is conflicting advice on population trends: survey catch rates of juveniles are increasing but medium-sized skates (including blonde ray), have shown long-term population declines between 1901-1907 and 1989-1997. There is evidence that the stock has been overexploited. Blonde ray is assessed as Near Threatened by the IUCN.

Scientists recommend that under a precautionary approach, no more than 895 tonnes are caught in each of 2017 and 2018. However, recent years landings have stabilised around 1170 tonnes per year.

In the Irish and Celtic Sea, the Blonde Ray has a patchy distribution but can be locally abundant on particular grounds. The patchy distribution of this species makes it difficult for scientists to interpret survey data, and its tendency to form aggregations makes it vulnerable to localized depletion. Also, the quality of landings data has too poor to create stock assessments. This has improved in recent years but more information is required on discards and their survival rates to determine the true level of mortality caused by fishing.

Over the past 7 years or more the North Devon Fishermen’s Association (NDFA) have collected species-specific landings data for Blonde and other ray species in the Bristol Channel. These data show that landings are increasing despite reduced effort in the fishery suggesting the Blonde ray population in the fished area is stable and the fishery sustainable.

Management

Criterion score: 0.75 info

There are no management plans or objectives for this species. Skates and rays are managed under five regional quotas (called TACs) applied to a group of species. This has been deemed as an unsuitable method for protecting individual species, but species-specific quotas may not be suitable because it may increase unnecessary discarding of skates and rays.

Other management methods are currently being considered at an EU level. Methods to avoid catching rays include closed areas and seasons and modifying fishing gear to observe their escape behaviour and design fishing gear accordingly. However, it is difficult to avoid catching rays in fishing gear (because of their peculiar shape) so fishing gear modifications have been suggested to improve the potential survival of rays so that they can be quickly and safely discarded.

There is no official minimum landing size for many skates and rays outside the 6 nautical mile limit in European waters. However, some inshore areas mandate a minimum landing size (40-45 cm disc width). There is direct management of fishing effort, depending on fishing gear, mesh size and area, however, this only applies to vessels of >15 m and therefore, inshore (generally smaller) fleets are generally not effort managed to the same extent. There are catch composition rules limit the percentage of skates that can be landed by demersal otter trawls (dependent on the mesh size of the net).

More information is needed on skate and ray catches, discard and survival rates. Landings data doesn’t tell scientists much about the health of the stock. The Fisheries Science Partnership project connects fishermen and scientists to fill in important knowledge gaps.

Surveillance legislation is underpinned by EU Law, and requires all vessels above 12m in length use vessel monitoring systems (VMS), and mandate at-sea and aerial surveillance and inspections of vessels, logbooks and sales documents.

Some protected areas have been designated in these waters but offshore areas are not sufficiently managed. Some of these MPAs are designated to protect rays but more management and protection is required to prevent over-exploitation of these animals and their habitats.

Capture Information

Criterion score: 0.75 info

This is the main target species in the southern Irish Sea skate fishery, and an important target in the Bristol Channel skate fishery. It is normally taken by bottom trawl gears. Blonde ray is usually caught as bycatch but may be targeted on a seasonal basis.

Bycatch
Otter trawls are not a very selective gear. The catch may include a large variety of species such as various soles, plaice, monkfish, haddock, cod, John Dory, red gurnard, horse mackerel, boar fish and grey gurnard, skates, rays and starry smooth-hound.

ETP species can occasionally be caught in offshore otter trawl fisheries but it is illegal to land these species.

Discards
Because skate and rays are a peculiar shape and size, it is difficult for them to escape from fishing gear once caught. Therefore, other methods must be used to increase their likelihood for survival: skates and rays are generally a hardly species but their survival rate after discarding is extremely variable depending on fishing and handling methods: discard survival varied between 25%-100% in beam trawl surveys. In this specific area, discarding rates and survival is unknown.

As part of the cod-recovery plan trawlers have Square Mesh Panels (SMPs) which allows bycatch species to escape the nets including dogfish. Dogfish have really rough skin which harms other species in the net. By allowing them to escape, it means that skates and rays are more likely to be discarded alive. Discards of other species may include undersized or unmarketable fish or because they are choke species. Discards rates vary dramatically (30 - 70%).

Habitat
Bottom trawling has the potential to cause significant impact to habitat such as removing or destroying physical features and reducing biota and habitat complexity. Therefore, the recovery time of the seabed after trawling varies greatly and depends on the fishing gear, the substrate, intensity of the trawl and accustomed the seabed is to natural disturbance. Fishing occurs over a mixture of seafloor types e.g. sandy, muds, gravel. IFCAs ensure bottom trawling occurs in areas where there will be minimal damage to habitats such as mobile sands, however, in offshore areas, bottom trawling can occur over vulnerable habitats.

Alternatives

Based on method of production, fish type, and consumer rating: only fish rated 2 and below are included as an alternative in the list below. Click on a name to show the sustainable options available.

Dab
Halibut, Atlantic (Farmed)
Halibut, Pacific
Megrim
Plaice
Sole, Dover sole, Common sole
Sole, Lemon
Turbot (Caught at sea)
Turbot (Farmed)

References

ICES Advice 2016 Book 5. Blonde ray (Raja brachyura) in divisions 7.a and 7.f-g (Irish Sea, Bristol Channel, Celtic Sea North). Available at: http://ices.dk/sites/pub/Publication%20Reports/Advice/2016/2016/rjh-7afg.pdf

McCully, S. R., Scott, F., and Ellis, J. R. 2012. Lengths at maturity and conversion factors for skates (Rajidae) around the British Isles, with an analysis of data in the literature. -ICES Journal of Marine Science, 69: 1812-1822.

Marandel, F., Lorance, P., Andrello, M., Charrier, G., Le Cam, S., Lehuta, S. Trenkel, V.M. 2017. Insights from genetic and demographic connectivity for the management of rays and skates. Canadian Journal of Fisheries and Aquatic Sciences IN PRESS.

Scientific, Technical and Economic Committee for Fisheries (STECF) - 56th Plenary Meeting Report (PLEN-17-03); Publications Office of the European Union, Luxembourg.